Sewer project will close part of Terwilliger this fall for up to a year

A sewer installation project tentatively scheduled to begin this fall will close a segment of Terwilliger Boulevard just north of Lake Oswego for up to a year, rerouting traffic to Highway 43 and Taylors Ferry Road.

Portland city officials are trying to get the word out while there are still several months to go before the project gets underway, but commuters are already unhappy about the potential increase in congestion and travel times, and Dunthorpe residents say theyre alarmed by the prospect of traffic cutting through their neighborhood.

Theres no law enforcement in that neighborhood  zero police presence, says Dunthorpe resident Kevin Wright. People will take advantage of that.

The project will install an 8-inch-wide, 7,000-footlong sewer pipe underneath Terwilliger Boulevard, stretching from a pumping station near Powers Court to the junction with Highway 43. The new line will allow sewage to flow to the Tryon Interceptor sewer, which carries sewage to the Portland-owned Tryon Creek Wastewater Treatment Plant in Lake Oswego.

Allowing the sewage to flow downhill instead of pumping it back to the main Portland plant will eliminate the need for the Terwilliger pumping station, which Portland officials say has become costly to maintain. It will also provide a future sewer connection for new developments in the area, as well as for existing homes that currently use septic systems.

(The area) is a hodgepodge of the Multnomah County sewer district, the Riverdale-Dunthope (sewer district) and the on-site septic systems that have a poor history of operation, says Project Manager John Houle. And the pump station is at the end of its useful life. So this will eliminate that pump station and also provide sewerage to an underserved part of the city.

But installing the pipe will require excavating a deep trench in the center of Terwilliger Boulevard, and the road will have to be completely closed for the duration of the project  from a point near the Iron Mountain Trailhead all the way to Highway 43. Traffic will be diverted to Highway 43, with Taylors Ferry Road serving as the detour connection between Terwilliger and the highway.

Terwilliger is a very narrow, winding country road, and in some portions the sewer is very deep and access is very limited for some of the equipment that may be required to build the sewer, says Houle, a supervising engineer with the City of Portland. So we thought, Well, to expedite the process, lets look at closing the road and giving the contractor full ability to stage and do the work as efficiently as possible.

The project was originally scheduled to begin nearly two years ago, but was put on hold until after the completion of the new Sellwood Bridge to avoid hitting drivers on Highway 43 with two sources of congestion at once.

We were cognizant of the role Terwilliger plays in traffic circulation through southwest (Portland), Houle says.

With the Sellwood bridge construction scheduled to be finished in November, though, officials have begun to pick up where they left off. A request for proposals from contractors is being finalized, Houle says, but the City does not expect to receive any replies until late summer. The project is scheduled to begin in the fall, although a specific start date has not been finalized.

But even without the Sellwood Bridge thrown into the mix, the prospect of shutting down Terwilliger Boulevard for up to a year remains unpalatable for Dunthorpe residents. At a meeting on March 10, Portland engineering officials offered a more detailed explanation of the planned detours and fielded questions from a number of commuters and residents.

I know concerns people spoke about at the meeting were, of course, Can we shorten the duration? Houle told The Review after the meeting. And were going to try to do everything we can. The closure will serve that purpose, to try to be as efficient and quick as possible in terms of not closing it for an entire year.

More than 30 people attended the open house, and almost all of them were unhappy about the traffic impacts that the closure will likely create  both on Highway 43 and in Dunthorpe itself.

Many meeting attendees questioned whether alternative options had been considered, such as upgrading the pumping station on Terwilliger or relocating the pipe to one side of the road so that traffic could still pass through on the other side during construction.

I think this thing started out with the wrong assumption, which is that you can close Terwilliger. No one said, You cant, said Dunthorpe resident Gerald Fox, who advocated moving the pipes location. Its solvable, except they think they dont have to do that.

Officials acknowledge the difficulties that the closure will bring, but say it is unavoidable. According to Houle, keeping one lane of traffic open would require flaggers to work 24 hours a day and create long wait times for drivers. It would also extend the project significantly, because the contractor would not be able to use the road as a staging area.

A lot of times, youll see contractors occupy an empty lot or something and put their equipment and materials on it. Terwilliger doesnt allow that very easily, Houle says. Not closing the road might require the contractor to mobilize to the site every day, because theres very limited parking and access.

Another major point of contention: Officials plan to put up extensive signage to steer drivers to the detour route, but many meeting attendees said they thought rushed drivers will inevitably be tempted to ignore the signs and cut through the neighborhood.

Those commuters will have a hard time in Dunthorpe, residents said, because the neighborhood was not designed for heavy traffic. The roads are all very narrow, with lots of curves and no room to pull over. And the traffic grid is complicated for those unfamiliar with it, with lots of twists and turns.

In addition to bringing in unwanted traffic, the closure will also impact Dunthorpe residents by adding to their travel time, particularly for those who live at the southern end of the neighborhood. For Birdshill residents heading south, for example, driving out to Highway 43 will take longer than using Terwilliger.

I figure I have to add 15 minutes to anywhere I want to go once it starts, said Birdshill resident Amy Marks.

Several residents at the meeting also referenced a recent accident on Highway 43 that they said could be an uncomfortable preview of what the traffic situation could look like on a bad day. On the morning of March 3, a two-car accident resulted in a portion of the highway being shut down. Southbound traffic was rerouted through Dunthorpe to Terwilliger, and the results were unpleasant for neighborhood residents.

Everyone was looking at their phones for directions and there were schoolchildren walking around, said Dunthorpe resident Leslie Gross.

I counted 50 cars and a TriMet bus, Coit added.

Houle says Portland city officials will try to address those issues. But he also says that some the residents concerns relate to existing problems with the roads and cant be fixed as part of the project.

They talked about speeding cars going through this neighborhood with no sidewalks and children on the street. Thats happening now, and its an issue that needs to be taken up with the county, Houle says. But we will try to mitigate our impacts to make sure were not worsening it. Anything we can do, we will.

Clackamas County Engineer Rick Nyes told The Review that the county would be open to the possibility of putting speed bumps in Dunthorpe, which was a frequent request at the March 10 meeting. He said the county would have to work with the City of Portland to install them, though, because the county only controls some of the roads in the neighborhood.

Wed rely on the city to do that as a temporary measure, because only very small sections of the roads are county roads, he says. I think thats a possibility if there were some temporary speed bumps or something that would help both regulate speed as well as discourage the use of those roads. I think wed be open to that.

Its difficult for any single governing body to make changes to all the roads involved, because Terwilliger runs through or near several different jurisdictions. The lower 4,000 feet of the future pipe will be in Clackamas County, while different parts of the upper 3,000 feet will be in either Multnomah County or the City of Portland. But ultimately, Portlands Bureau of Environmental Services is the agency doing the actual construction, so city staff have to coordinate with both counties at each stage of the project.

They need to be contacted and they need to approve the construction methods for restoring the road to its original condition, because (the project involves) a utility in their jurisdictions, Houle says. So thats all part of the process.

City and county officials agree that commuters should be kept out of Dunthorpe, but they say there are limits to what the agencies can do.

To some degree, its going to be the people who want to use those roads making decisions for themselves on which is the best route to use, Nyes says. You can try to encourage people to follow the detour route by adding detour signs and trying to get them to use the better intersections. But unless someone decides that these roads need to be completely closed off or something, theyre public roads, so people can use them.

The overlapping jurisdictions proved to be a frustrating issue for attendees at the March 10 meeting. Multiple residents voiced concerns about the left-hand turns that northbound drivers on Highway 43 would have to make in order to turn into Dunthorpe. Most of those turns are unprotected, and residents viewed the intersections as hazardous. There were also several calls to lower the speed limit on Highway 43. But Highway 43 isnt controlled by Portland or the counties; its controlled by yet another agency: the Oregon Department of Transportation.

It doesnt seem as though anyone is really taking ownership, Coit told The Review at the meeting. It doesnt seem to me, as a resident, that theres any coordination.

Nyes says Clackamas County cant change the highway, but acknowledges the difficult left turns and intersections.

All those intersections  theyre not county intersections, theyre ODOT. And theyre pretty rough, he says. We havent provided any recent comments on the detour plan, but were aware that there are issues with all those intersections, and well recommend whatever we can to try to get people to not use those as detour routes.

Houle points out that some details of the project may change before things get started in the fall. At the moment, the project still doesnt have a contractor lined up; the current plan outlines the conditions the City of Portland will impose when it solicits bids for the project, but its not final.

Regardless of who does the actual work, Houle says, officials will try to make the project go as quickly as possible.

Were in the process of writing specifications, and we dont have a contractor on board, he says, so we will make our wishes known in the contract documents that are prepared, compressing the timeline as much as possible.

Nyes says Clackamas County will also review each step of the process and provide input if staff members see a way to speed things up.

Wed have involvement in terms of the closure duration, he says. Well look at their plan and see if theres some room to tighten it up if its a long window. But sometimes, just based on the conditions, its hard to determine exactly how long a road needs to be closed.

Traffic plans may also be adjusted depending on how the contractor approaches the project, and Houle says the City of Portland also plans to use the months before the project starts to gather more traffic information about Terwilliger Boulevard and refine the detour plans. The final outcome might be less of a headache, he says, but officials would rather prepare residents for the worst-case scenario until all the details are known.

There may be a different method of construction that the contractor proposes, he says. But we didnt want to prepare (residents) for no impact and then say, By the way, were closing the road tomorrow because the contractor needs to work safely in this narrow little corridor. So that all played into the decision process.

Contact Anthony Macuk at 503-636-1281 ext. 108 or This email address is being protected from spambots. You need JavaScript enabled to view it..